<!doctype html> 
<html> 
<head> 
    <meta charset="utf-8"> 
    <title></title> 
    <style type="text/css">

.div{width: 200px;height: 200px;background: black;-webkit-clip-path:polygon(50% 0%,100% 100%,0 100%);}


    </style>
</head>
<body>
<div class='div'></div>

</body>
</html>